Granted Patent
Utility
US 4,417,229 · App. 06/375,393
Means for use on a railroad to distinguish between traction current and signal current
Inventor:
H. James Wilson
Patented Case
View Patent ↗
Granted: Nov 22, 1983
Filed: May 6, 1982
Inventor
H. James Wilson
Assignee (at issue)
Safetran Systems Corporation
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.